This invention relates to caster assemblies for household appliances and the like, and relates more particularly to a caster assembly substantially all of which is constructed of molded plastic elements.
Typical prior art constructions for so-called swivable casters are disclosed in U.S. Pat. No. 3,894,310, issued July 15, 1975 to S. T. Screen for a Twin-wheeled Castor; U.S. Pat. No. 3,822,437 issued July 9, 1974 to S. T. Screen for Castors; U.S. Pat. No. 4,361,930 issued Dec. 7, 1982 to R. E. Seesengood for Caster Socket Assembly; U.S. Pat. No. 4,068,342 issued Jan. 17, 1978 to V. J. Carrier for Castor Support Structure; and British Patent Specification No. 1 533 982 to E. G. Clark for Furniture Glides and Castors, published Nov. 29, 1978.
Castor assemblies of the foregoing patents, as well as other prior art castor assemblies were unnecessarily expensive insofar as labor and/or material costs, and/or were found to have unacceptable short life spans because of force concentrations on elements that were not constructed to withstand such forces. For example, the aforesaid Carrier U.S. Pat. No. 4,068,342, discloses a structure having expensive ball bearings to permit swiveling. This expensive bearing construction is also found in the Seesengood U.S. Pat. No. 4,361,930.
In many prior art constructions, the socket is constructed to provide a wedge like fit that is used to hold the other caster members in assembled relationship. This puts an unnecessary strain on the socket forming part and/or requires that an additional sleeve be interposed between the wall of the socket and a swivable stem that is disposed within the sleeve.